The present invention relates to methods for producing chewing gums. In particular, the invention relates to a method for quickly eliminating agglomerated masses from chewing gums made by continuous extrusion.
The batch method of producing chewing gums has long been considered the standard for producing chewing gums on a commercial scale. Such methods, however, tend to be labor intensive and produce chewing gums of varying consistency. The batch process typically requires using large kettles for the extensive mixing and kneading of a gum base and plasticizers into a viscous melt. Thereafter, softeners and bulking agents such as sugars or sugar alcohols are added to the molten mass with stirring. Later, flavorings, such as flavor oils and/or spray-dried flavors, and sweeteners are added while mixing is continued until a homogenous mass is achieved. The chewing gum mass is thereafter cooled and then later rolled, scored and wrapped into the final product.
The above described method often required multiple mixing steps and transferral of the gum mass from various production apparatus and work areas until the final product was completed. Further, since the batch process is unmechanized, the various mixing and kneading steps require the continuous attention of the chewing gum artisan to determine when ingredients are to be added to the batch. Since the timing of the ingredient additions to the molten mass is subjectively based, the final products often varied in texture and/or flavor from batch to batch.
Over the years, various attempts by the industry to replace the batch process for the bulk manufacture of chewing gums have been made. U.S. Pat. Nos. 1,852,005 and 1,953,295 disclose early continuous production methods and apparatus for producing chewing gum strips. While providing continuous output of a chewing gum slab, these attempts have several shortcomings. For example, these patents disclose methods using a single entry port for the ingredients and subjecting all of the ingredients to plasticizing temperatures throughout an extrusion process before allowing a gum slab to exit. These methods, therefore, did not provide for differentiation between the chewing gum ingredients. Other deleterious effects on chewing gums associated with these methods include delicate ingredients such as flavor oils "flashing off" or degrading due to prolonged exposure to high temperatures and considerable pressure and/or incomplete integration of ingredients during extrusion. Incomplete mixing results in agglomerations of powdered gum bases and/or bulking agents such as sugar passing through the extruder and into the final product.
U.S. Pat. No. 3,455,755 discloses a method and apparatus for continuously casting slabs of chewing gums and for accordion-like pleating and stacking of the slab. This method, however, like the earlier methods described, relies upon a single entry port for introducing all of the chewing gum ingredients and, therefore, fails to address the separate mixing needs of the individual gum ingredients. By limiting introduction of the ingredients to a single port, some ingredients are mixed longer than necessary, while other ingredients like bulking agents such as sugar may not be mixed enough. Moreover, improper integration of the gum ingredients into the gum product is known to result in visible agglomerations in the final product. These imperfections in the method tend to produce a gum with inferior organoleptic qualities. The ability to precisely locate the crucial entry points for the chewing gum ingredients to provide complete mixing without damaging the ingredients is not disclosed. U.S. Pat. No. 3,644,169 has a similar disclosure to that of U.S. Pat. No. 3,455,755 described above.
More recently, U.S. Pat. No. 4,555,407 discloses a method for continuously forming wide, thin chewing gum slabs using a twin screw extruder. According to this method, a chewing gum paste is formed by continuously introducing into a first feed port of an extruder pelletized gum base, corn syrup, a portion of granulated sugar, plasticizer and coloring ingredients. The remaining sugar is introduced into a second port just past the first feed port while flavoring ingredients are added further downstream. Thus, while providing a continuous method for producing a gum paste slab, there is no suggestion that the agglomerations of solid chewing gum ingredients such as granulated sugar and/or bulking agents could be significantly reduced within the extruder to improve the final chewing gum product.
In the past, the additional mixing required to integrate the refractory agglomerations into the final chewing gum product was typically carried out by two directional mixing. This forward and reverse action would usually reduce agglomerations, but at substantial cost. At a minimum, the increased mixing time slows down the continuous production. Moreover, extended mixing can have harmful effects on sensitive chewing gum ingredients. By lengthening the time the ingredients are in the extruder and exposed to the high temperatures and high pressures which accompany such intense mixing, the integrity of the final gum product can be compromised.
It is also known that overzealous attempts at combining all chewing gum ingredients at a single entry point in the extruder barrel can result in the backing-up of the powdered ingredients at the source. When this phenomena occurs, the throughput must be discarded or reworked since the proportion of gum base to the powdered ingredients becomes skewed.
Accordingly, a need still exists for an improved method for the continuous production of chewing gum products.
It is, therefore, an object of the present invention to provide a method for continuously preparing chewing gums with minimum time for reducing the agglomerations of chewing gum ingredients within an extruder.
It is another object of the present invention to provide a method for the continuous preparation of chewing gums which avoids back-up of the powdered ingredients at the source of introduction.